labyrinth (wave,queue)

#include<iostream>
#include<queue>
using namespace std;
char a[1111][1111];
int ans[1111][1111],n,m;
void wave(int x,int y)
{
    queue<pair<int, int> > q;
    pair<int, int> p;
    q.push(make_pair(x, y));
    while(!q.empty())
    {
       p = q.front();
       q.pop();
       x = p.first; y = p.second;
       if(x-1>=0 && a[x-1][y]!='#' && !ans[x-1][y]){
          ans[x-1][y]=ans[x][y]+1;
          q.push(make_pair(x-1, y));
       }
       if(y+1<m && a[x][y+1]!='#' && !ans[x][y+1]){
          ans[x][y+1]=ans[x][y]+1;
          q.push(make_pair(x, y+1));
       }
       if(x+1<n && a[x+1][y]!='#' && !ans[x+1][y]){
          ans[x+1][y]=ans[x][y]+1;
          q.push(make_pair(x+1, y));
       }
       if(y-1>=0 && a[x][y-1]!='#' && !ans[x][y-1]){
          ans[x][y-1]=ans[x][y]+1;
          q.push(make_pair(x, y-1));
       }
   }
}
int main()
{
   int i, j,startx,starty,endx,endy;
   cin>>n>>m;
   for(i=0; i<n; i++)
      for(j=0; j<m; j++)
      {
          cin>>a[i][j];
          if(a[i][j]=='*'){startx=i;starty=j;}
          if(a[i][j]=='$'){endx=i;endy=j;}
      }
   wave(startx,starty);
   cout<<ans[endx][endy];
   return 0;
}